Litter Birth Research Articles

Estimation of Genetic Parameters for the Litter Size and Birth Weight in Korean Black Goats

Estimation of Genetic Parameters for the Litter Size and Birth Weight in Korean Black Goats

Ectoparasites and fitness of female Columbian ground squirrels.

Parasites play an important role in the evolution of host traits via natural selection, coevolution and sexually selected ornaments used in mate choice. These evolutionary scenarios assume fitness costs for hosts. To test this assumption, we conducted an ectoparasite removal experiment in free-living Columbian ground squirrels (Urocittelus columbianus) in four populations over three years. Adult females were randomly chosen to be either experimentally treated with anti-parasite treatments (spot-on solution and flea powder, N = 61) or a sham treatment (control, N = 44). We expected that experimental females would show better body condition, increased reproductive success and enhanced survival. Contrary to our expectations, body mass was not significantly different between treatments at mating, birth of litter or weaning of young. Further, neither number nor size of young at weaning differed significantly between the two treatments. Survival to the next spring for adult females and juveniles was not significantly different between experimental and control treatments. Finally, annual fitness was not affected by the treatments. We concluded that females and their offspring were able compensate for the presence of ectoparasites, suggesting little or no fitness costs of parasites for females in the different colonies and during the years of our experiments.

Immunocompetence and reproductive characteristics of Campbell’s dwarf hamster males selected for low and high humoral immune response on sheep red blood cells (SRBC): Testing the immunocompetence handicap hypothesis

Characteristics of innate (nonspecific) and acquired T-cell immunity, resting metabolic rate, hormonal and reproductive status, morphological traits of maturation and aggressive behavior were studied in two sample groups of Campbell’s dwarf hamster males (Phodopus campbelli Thomas, 1905) selected in three generations for high and low humoral immune response to sheep red blood cells (SRBC). The groups of males with low and high immune responses (LIR and HIR, respectively) to SRBC did not differ statistically in the intensity of delayed-type hypersensitivity cutaneous response to phytohemagglutinin (T-cell immunity test), the activity of the peroxidase-endogenous hydrogen peroxide system of neutrophils (characteristic of the innate immunity state), the white blood cell counts, the resting metabolic rate, body weight, anogenital distance at the age two months, testosterone level in the blood before immunization and at the peak of secondary immune response to SRBC, or the blood cortisol level in response to social conflict (encountering). LIR males had a significantly higher background blood cortisol level and were less aggressive (reaction to the stranger male). The midventral sebaceous gland was less developed in them at the age of two months. We observed no differences in the time of first litter birth after uniting LIR and HIR males in pairs with intact females; however, females in pairs with LIR males had smaller numbers of pups in the litter. The results of comparison do not favor the immunocompetence handicap hypothesis, which assumes the existence of a trade-off between the immunocompetence and reproductive effort.

Pigs, Purity, and Patrilineality: The Multiparity of Swine and Its Problems for Biblical Ritual and Gender Construction

The biblical characterization of pigs as impure has been interpreted in a variety of ways. Most have focused on the anomalies of the pig compared with other domesticated animals, especially with regard to their alimentary processes. All interpretations, however, have neglected a primary feature of pigs that makes them radically different from all other clean land animals, namely, that they are multiparous, giving birth in litters. This article argues that the multiparity of pigs makes them incompatible with other ritually clean land animals in four ways: (1) All clean land animals are uniparous. (2) As multiparous animals, pigs do not bear a true firstborn male, which would make them different from all clean domesticated animals. This feature is most important because the sanctity of the domesticated firstling is recognized by all pentateuchal sources, and, furthermore, the ideology of the firstborn male is integrally related to the human practices of inheritance, lineage, and wealth management. (3) The multiparity of pigs highlights abundant female fertility in comparison with the more controlled and managed fertility seen in the biblical purity systems. (4) Multiparous animals are capable of bearing the offspring of multiple sires simultaneously, a phenomenon that conflicts with the biblical focus on paternity.(ProQuest: ... denotes non-US-ASCII text omitted.)The cultural anthropologist Claude Levi-Strauss famously stated that animals used in specific rituals are often chosen not because they are to eat but because they are good to think.1 By this he meant that many cultures use animals to act out concepts fundamental to their particular view of the world, especially various aspects of their structure. Following him, Howard Eilberg-Schwartz argues that this is especially true for rituals involving animals in the Hebrew Bible. In his view, animals, as well as other aspects of the natural world, become material on which the ancient Israelites and Jews played out fundamental social metaphors. Vital concerns about the world were acted out not only in society itself but also on the materials that intersected with it; the natural world in general was a mirror that both reflected Israelite experience of life and served as a model for what Israelite communal and individual life should and could be.2 According to Eilberg-Schwartz,A number of [biblical] rituals can be interpreted as acting out or living out the implications of those metaphors which dominate Israelite thought. This process ... is most obvious in the correspondence that one finds between some of the rules regulating the life of Israel and the rules governing the treatment of livestock and agricultural activity. If the flocks, herds and fields are metaphors for Israelites, then it follows that one should act towards the former in the same way that one acts towards the latter.3Eilberg-Schwartz shows, for instance, that the laws of the Torah specify that not only should the Israelites observe the Sabbath, but their animals should do the same (Exod 20:9, 23:12, Deut 5:14). Including animals in this scheme illustrates the fundamental nature of the Sabbath and the concept that the Sabbath is built into the very structure of the natural world. Other examples include the symmetry of the prohibition on trimming the edges of one's facial hair with the ban on reaping the edges of a field (Lev 19:9, 27), or the parallelism between keeping an infant animal with its mother for seven days before slaughtering it (Exod 22:29, Lev 22:27) and keeping an infant boy with its mother for seven days before his circumcision (Lev 12:3).In a similar vein, this study questions whether the biblical writers considered the pig to be impure because it is an unfit model for human societal behavior. Unfortunately, it is unclear which aspect of the pig makes it unfit. As is well known, the rationale for the prohibition of pork is enigmatic and unclear. …

Effects of dietary enrichment with a marine oil-based n-3 LCPUFA supplement in sows with predicted birth weight phenotypes on birth litter quality and growth performance to weaning

The effects of a marine oil-based n-3 long-chain polyunsaturated fatty acid (mLCPUFA) supplement fed to the sow from weaning, through the rebreeding period, during gestation and until end of lactation on litter characteristics from birth until weaning were studied in sows with known litter birth weight phenotypes. It was hypothesized that low birth weight (LBW) litters would benefit more from mLCPUFA supplementation than high birth weight litters. A total of 163 sows (mean parity=4.9±0.9) were rebred after weaning. Sows were pair-matched by parity and litter average birth weight of the previous three litters. Within pairs, sows were allocated to be fed either standard corn/soyabean meal-based gestation and lactation diets (CON), or the same diets enriched with 0.5% of the mLCPUFA supplement at the expense of corn. Each litter between 9 and 16 total pigs born was classified as LBW or medium/high average birth weight (MHBW) litter and there was a significant correlation (P<0.001) between litter average birth weight of the current and previous litters within sows (r=0.49). Sow serum was harvested at day 113 of gestation for determination of immunoglobulin G (IgG) concentrations. The number of pigs born total and alive were lower (P=0.01) in mLCPUFA than CON sows, whereas the number of stillborn and mummified pigs were similar between treatments. Number of stillborns (trend) and mummies (P<0.01) were higher in LBW than MHBW litters. Tissue weights and brain : tissue weight ratios were similar between treatments, but LBW litters had decreased tissue weights and increased brain : tissue weight ratios compared with MHBW litters. Placental weight was lower (P=0.01) in LBW than MHBW litters, but was not different between treatments. Average and total litter weight at day 1 was similar between treatments. mLCPUFA increased weaning weight (P=0.08) and average daily gain (P<0.05) in MHBW litters, but not in LBW litters. Pre-weaning mortality was similar between treatments, but was higher (P<0.01) in LBW than MHBW litters. IgG concentration in sow serum was similar between treatments and litter birth weight categories. In conclusion, litter birth weight phenotype was repeatable within sows and LBW litters showed the benchmarks of intra-uterine growth retardation (lower placental weight and brain sparing effects). As maternal mLCPUFA supplementation decreased litter size overall, only improved litter growth rate until weaning in MHBW litters, and did not affect pre-weaning mortality, maternal mLCPUFA supplementation was not an effective strategy in our study for mitigating negative effects of a LBW litter phenotype.

52. Developmental programming of body weight, microglial development, and behavior by high-fat and BCAA-supplemented diets

Maternal obesity during gestation/lactation can “program” offspring for increased obesity themselves, along with increased vulnerability to mood disorders. Emerging evidence suggests that this programming by perinatal diet is propagated via inflammatory mechanisms, specifically linked to two components that are enriched in a “Western diet”: saturated fatty acids and branched-chain amino acids (BCAAs). We tested the hypothesis that these components would synergize to result in exacerbated brain and behavioral consequences in offspring. We placed female mice on one of 4 diets: (1) high-fat diet (HFD), (2) low-fat diet (LFD), (3) HFD supplemented with BCAA (HFD + BCAA), or (4) LFD supplemented with BCAA (LFD + BCAA) for 6 weeks prior to breeding, resulting in the following weight pattern: HFD + BCAA > HFD = LFD/BCAA > LFD. Although the pregnancy success rate of HFD groups was less than half that of the LFD groups, all groups had comparable litter sizes and birth weights. RT-PCR analysis of offspring brains at postnatal day (P)1 revealed that HFD and HFD + BCAA pups had decreased expression of microglial markers (e.g., Iba-1, CD11b), suggesting that microglial colonization and maturation may be delayed. By P28, HFD pups weighed more than LFD, whereas both BCAA groups weighed significantly less. Finally, in adulthood, HFD and HFD + BCAA offspring showed signs of increased anxiety and depressive-like behavior. In sum, perinatal diet, particularly HFD, can program body weight, microglial development, and behavior of offspring.

Preweaning mortality in group-housed lactating sows: Hormonal differences between high risk and low risk sows

This study used an endocrinological approach to explain the differences between sows that have higher vs. lower preweaning mortality in a group-farrowing system. The association between sows that had 2 or more piglets die within the first 72 h postfarrowing (high risk) or sows that had 1 or no piglets die within the first 72 h postfarrowing (low risk) with changes in serum hormone concentrations was investigated. Multiparous sows (n = 63; parity 2 to 7) from 4 contemporary breeding groups, each mated within a week, were used. Sows were housed in a group-farrowing system where 8 sows farrowed in individual pens and shared a communal feeding and dunging area in each room. Reproductive performance, including total born, born alive, and stillborn per litter, individual weight of piglets at birth and weaning (at 5 wk postfarrowing), litter size at weaning, preweaning mortality of piglets, and sow BW before farrowing and after weaning, were recorded for all sows. Of these sows, 14 sows from 2 breeding groups were selected randomly for blood sampling through an indwelling ear vein catheter. A blood sample was collected daily from each sow 2 d prefarrowing through 2 d postfarrowing. Serum samples were analyzed for prolactin, oxytocin, cortisol, and urocortin concentrations using RIA. Among the 14 sows, 7 sows lost 2 or more piglets during the first 72 h after farrowing and were classified as high risk sows, and the other 7 sows lost 0 or 1 piglet during the same period and were classified as low risk sows. Catheters in 11 sows (5 high risk sows and 6 low risk sows) remained functional for the entire sampling period. Results indicate that high risk sows farrowed larger litters (live born = 13.8 ± 0.50 vs. 11.3 ± 0.48 piglets; P = 0.03) with lighter piglets (1.4 ± 0.04 vs. 1.7 ± 0.05 kg; P < 0.001) compared with low risk sows. In addition, high risk sows had greater oxytocin concentrations (0.09 vs. 0.07 ng/mL; SE = 0.02, P = 0.01), which might be associated with larger litters farrowed, compared with low risk sows. There were no differences between high risk and low risk sows (P > 0.30) in terms of serum prolactin, cortisol, or urocortin concentrations. These results suggest that litter size and birth weight of piglets played an important role in preweaning mortality of piglets and hormone concentrations in sows were not associated with piglet mortality in the group-farrowing system used.

사료 내 이탈리안 라이그라스 펠렛의 첨가급여가 임신모돈의 번식성적에 미치는 영향

The aim of this study was to investigate the effects of dietary supplementation of pelleted-Italian Ryegrass (IRG) as a source of fiber on reproduction performance in pregnant sows. A total of 24 pregnant sows were randomly assigned to four dietary treatments, which was given a corn-soybean diet with 0%, 10%, 20%, and 30% pelleted-IRG from 105 days prepartum to 7 days postpartum. During experimental period, the sows fed the IRG supplemented diet showed the lower feed intake than the sows fed the control diet (p<0.05). The changes of body weight in sows from initial to pre- and/or post-partum was significantly smaller in sows fed the IRG supplemented diet than control group. It is thought that the lower weight gain in IRG supplemented groups is caused by low feed intake. Although there was no significant difference, sows fed the IRG supplemented diet tended to increase the litter size and birth weight in piglets compared with sows fed the control diet. This result suggests that the dietary supplementation of IRG has the positive effects to improve the reproductive performance in sows. But, the excessive feeding of IRG to sows might cause to retard the days of return to estrus, and decrease the contents of solid, milk protein, and milk fat in colostrum. Thus, the addition of about 10% IRG is desirable to increase the reproductive performance. Meanwhile, the feeding energy diet is better effective than feeding the fiber diets to improve overall productivity in sows after postpartum.

Effect of premature birth on retinal vascular development in the neonatal rat

To study the effects of premature birth on the development of rat retinal vasculature. Experimental study. Sixty pregnant Sprague-Dawley rats were divided into four groups: bacterial lipopolysaccharide-induced preterm group (LPS group), RU-486 induced preterm group (RP group), cesarean section induced preterm group (CP group), and the normal delivery rats as the control group. The weight of rats from each group was recorded until postnatal day 21. On postnatal day 4, 7, 10 and 14 (P4, P7, P10 and P14), the retina of right eye was dissected and whole-mounted. Each premature group was divided into two subgroups based on the number of rats in each litter, the small subgroup (6-8 rats per litter, group 1) and the large subgroup (14-18 rats per litter, group 2). The development of retinal vascularization process was observed on P4, P7 and P10 (n = 6).Independent t test, one-way ANOVA and LSD-t test were used to analyzed the results. The weight of premature rats in LPS, CP and RP groups was significantly lower than that in the normal group within postnatal 21 days (LSD-t test: all P < 0.05). On the P4 and P7 in LPS group, the proportions of retinal superficial vascularized area of newborn rats [(0.47 ± 0.02) % ,(0.63 ± 0.04)%] were less than that in the normal group [(0.57 ± 0.04) % , (0.74 ± 0.05)%] (t4 d = 6.427, P 4 d = 0.000;t7 d = 5.111, P 7 d = 0.000). On the P4 and P7 in RP group, this proportions [(0.49 ± 0.04) %,(0.65 ± 0.04)%] were less than that in the normal group [(0.57 ± 0.04) %, (0.74 ± 0.05)%] (t4 d = 4.469, P 4 d = 0.000;t7 d = 2.491, P 7 d = 0.022). On P4, P7 and P10 in CP group, this proportions [(0.49 ± 0.05) %, (0.61 ± 0.05) %, (0.94 ± 0.03)%] were also less than that in the normal group[ (0.57 ± 0.04) %, (0.74 ± 0.05) %, (0.97 ± 0.02)%] (t4 d = 4.044, P 4 d = 0.001;t7 d = 6.011, P 7 d = 0.000; t 10 d = 2.331, P 10 d = 0.030). Retinal superficial vascularization completed on P14 in all groups. On the P4 and P7 in LPS group, the proportion of retinal vascularized area of group 2 [(0.44 ± 0.02)%, (0.60 ± 0.03)%] were less than that of group 1 [(0.53 ± 0.04)%, (0.74 ± 0.03)%] (t4 d = 3.852, P 4 d = 0.008; t7 d = 5.630, P 7 d = 0.001). On the P4 and P7 in CP group, this proportion in group 2 [(0.43 ± 0.02)%, (0.64 ± 0.03)%] were less than that of group 1 [ (0.54 ± 0.03)%, (0.76 ± 0.02)%] (t4 d = 4.695, P 4 d = 0.003; t7 d = 6.025, P 7 d = 0.001). On P4 in RP group, the proportions of group 2 [ (0.44 ± 0.01)%] was less than that of group 1 [ (0.54 ± 0.04)%] (t4 d = 5.000, P 4 d = 0.002). The premature rats have lower weight and much slower rate of early retinal vascularization, as compared with the normal rats. Furthermore, in the premature rats, the proportion of retinal vascularization in larger litters is less than that in smaller litters. These results indicate that premature birth and larger litter size have effects on the development of rat retinal vasculature.

Long-Term Effects of Early Overnutrition in the Heart of Male Adult Rats: Role of the Renin-Angiotensin System

To analyze the long-term effects of early overfeeding on the heart and coronary circulation, the effect of ischemia-reperfusion (I/R) and the role of the renin-angiotensin system (RAS) was studied in isolated hearts from control and overfed rats during lactation. On the day of birth litters were adjusted to twelve pups per mother (controls) or to three pups per mother (overfed). At 5 months of age, the rats from reduced litters showed higher body weight and body fat than the controls. The hearts from these rats were perfused in a Langendorff system and subjected to 30 min of ischemia followed by 15 min of reperfusion (I/R). The myocardial contractility (dP/dt) and the coronary vasoconstriction to angiotensin II were lower, and the expression of the apoptotic marker was higher, in the hearts from overfed rats compared to controls. I/R reduced the myocardial contractily, the coronary vasoconstriction to angiotensin II and the vasodilatation to bradykinin, and increased the expression of (pro)renin receptor and of apoptotic and antiapoptotic markers, in both experimental groups. I/R also increased the expression of angiotensinogen in control but not in overfed rats. In summary, the results of this study suggest that early overnutrition induces reduced activity of the RAS and impairment of myocardial and coronary function in adult life, due to increased apoptosis. Ischemia-reperfusion produced myocardial and coronary impairment and apoptosis, which may be related to activation of RAS in control but not in overfed rats, and there may be protective mechanisms in both experimental groups.

Mate choice for genetic compatibility in the house mouse.

In house mice, genetic compatibility is influenced by the t haplotype, a driving selfish genetic element with a recessive lethal allele, imposing fundamental costs on mate choice decisions. Here, we evaluate the cost of genetic incompatibility and its implication for mate choice in a wild house mice population. In laboratory reared mice, we detected no fertility (number of embryos) or fecundity (ability to conceive) costs of the t, and yet we found a high cost of genetic incompatibility: heterozygote crosses produced 40% smaller birth litter sizes because of prenatal mortality. Surprisingly, transmission of t in crosses using +/t males was influenced by female genotype, consistent with postcopulatory female choice for + sperm in +/t females. Analysis of paternity patterns in a wild population of house mice showed that +/t females were more likely than +/+ females to have offspring sired by +/+ males, and unlike +/+ females, paternity of their offspring was not influenced by +/t male frequency, further supporting mate choice for genetic compatibility. As the major histocompatibility complex (MHC) is physically linked to the t, we investigated whether females could potentially use variation at the MHC to identify male genotype at the sperm or individual level. A unique MHC haplotype is linked to the t haplotype. This MHC haplotype could allow the recognition of t and enable pre- and postcopulatory mate choice for genetic compatibility. Alternatively, the MHC itself could be the target of mate choice for genetic compatibility. We predict that mate choice for genetic compatibility will be difficult to find in many systems, as only weak fertilization biases were found despite an exceptionally high cost of genetic incompatibility.

Effects of Coronary Ischemia-Reperfusion in a Rat Model of Early Overnutrition. Role of Angiotensin Receptors

BackgroundObesity during childhood has dramatically increased worldwide in the last decades. Environmental factors acting early in life, including nutrition, play an important role in the pathogenesis of obesity and cardiovascular diseases in adulthood.AimsTo analyze the effects of early overfeeding on the heart and coronary circulation, the effect of ischemia-reperfusion (I/R) and the role of the renin-angiotensin system (RAS) were studied in isolated hearts from control and overfed rats during lactation.Methods and ResultsOn the day of birth litters were adjusted to twelve pups per mother (control) or to three pups per mother (overfed). At weaning (21 days) the rats were killed and the heart perfused in a Langendorff system and subjected to 30 min of ischemia followed by 15 min of reperfusion. The contractility (left developed intraventricular pressure) was lower in the hearts from overfed rats, and was reduced by I/R in hearts from control but not from overfed rats. I/R also reduced the coronary vasoconstriction to angiotensin II more in hearts from control than from overfed rats, and the vasodilatation to bradykinin similarly in both experimental groups. The expression of both angiotensin AGTRa and AGTR2 receptors was increased in the myocardium of overfed rats, and I/R increased the expression of both receptors in control rats but reduced it in overfed rats. The expression of apoptotic and antiapoptotic markers was increased in hearts of overfed rats compared with control, and further increased by I/R.ConclusionsThese results suggest that both overfeeding and I/R impair cardiac and coronary function due, at least in part, to activation of the angiotensin pathway. However, overfeeding may reduce the impairment of ventricular contractility by I/R.

Early Overfeed-Induced Obesity Leads to Brown Adipose Tissue Hypoactivity in Rats

Background/Aims: Brown adipose tissue activation has been considered a potential anti-obesity mechanism because it is able to expend energy through thermogenesis. In contrast, white adipose tissue stores energy, contributing to obesity. We investigated whether the early programming of obesity by overfeeding during lactation changes structure of interscapular brown adipose tissue in adulthood and its effects on thermogenesis. Methods: Birth of litters was considered day 0. On day 2, litter size was adjusted to normal (9 pups) and small (3 pups) litters. On day 21, the litters were weaned. A temperature transponder was implanted underneath interscapular brown adipose tissue pads of 81-day-old animals; local temperature was measured during light and dark periods between days 87 and 90. The animals were euthanized, and tissue and blood samples were collected for further analysis. The vagus and retroperitoneal sympathetic nerve activity was recorded. Results: Small litter rats presented significant lower interscapular brown adipose tissue temperature during the light (NL 37.6°C vs. SL 37.2°C) and dark (NL 38°C vs. SL 37.6°C) periods compared to controls. Morphology of small litter brown adipose tissue showed fewer lipid droplets in the tissue center and more and larger in the periphery. The activity of vagus nerve was 19,9% greater in the small litter than in control (p<0.01), and no difference was observed in the sympathetic nerve activity. In adulthood, the small litter rats were 11,7% heavier than the controls and presented higher glycemia 13,1%, insulinemia 70% and corticosteronemia 92,6%. Conclusion: Early overfeeding programming of obesity changes the interscapular brown adipose tissue structure in adulthood, leading to local thermogenesis hypoactivity, which may contribute to obesity in adults.

Comparison of Growth Performance of Antibiotic-free Yorkshire Crossbreds Sired by Berkshire, Large Black, and Tamworth Breeds Raised in Hoop Structures.

The objective of this study was to compare body weight, ADG, and feed:gain ratio of antibiotic-free pigs from Yorkshire dams and sired by Yorkshire (YY), Berkshire (BY), Large Black (LBY) or Tamworth (TY) boars. All the crossbred pigs in each of three trials were raised as one group from weaning to finishing in the same deep-bedded hoop, providing a comfortable environment for the animals which allowed rooting and other natural behaviors. Birth, weaning and litter weights were measured and recorded. From approximately 50 kg to market weight (125 kg), feed intake and body weights were recorded manually (body weight) or using a FIRE (Feed Intake Recording Equipment, Osborne Industries Inc. Osborne, Kansas) system with eight individual feeding stations. Feed intake data for 106 finishing pigs between 140 and 210 d of age and the resulting weights and feed conversion ratios were analyzed by breed type. Least square means for body weights (birth, weaning and to 240 d) were estimated with Proc Mixed in SAS 9.2 for fixed effects such as crossbreed and days of age within the sire breed. The differences within fixed effects were compared using least significant differences with DIFF option. Individual birth weights and weaning weights were influenced by sire breed (p<0.05). For birth weight, BY pigs were the lightest, TY and YY pigs were the heaviest but similar to each other and LBY pigs were intermediate. For weaning weights, BY and LBY pigs were heavier than TY and YY pigs. However, litter birth and weaning weights were not influenced by sire breed, and average daily gain was also not significantly different among breed types. Tamworth sired pigs had lower overall body weight gain, and feed conversion was lower in TY and YY groups than BY and LBY groups (p<0.05), however, number of observations was somewhat limited for feed conversion and for Tamworth pigs. Overall, no convincing differences among breed types were noted for this study, but growth performance in the outdoor environment was satisfactory.

High salt intake in pregnancy alters maturation of glomeruli in the rat offspring

There is currently discussion on the optimal salt intake and uncertainty whether both high and low salt intake is associated with adverse effects. One aspect has so far not be considered, i.e. the potential impact of salt intake during pregnancy on kidney function and blood pressure in the offspring. Faulty fetal programming, amongst others by high or low salt intake, leads to alterations in kidney morphology and albuminuria in the offspring. A low number of glomeruli is known to cause high blood pressure later in life. It was the purpose of the present study to clarify whether very high (or low) salt intakes in pregnancy affect kidney development in the offspring. Sprague-Dawley rats were fed normal (0.15%), medium (1.3%), or high (8.0%) salt diet during pregnancy and weaning. The number of glomeruli (mature, immature, and S-shape bodies) was assessed at 1 week postnatally. The expression of proteins of interest was assessed (by western blotting) at 1 week postnatally and at term. There was no difference between the groups with respect to litter size, birth weight, and placenta size. At age 1 week the number of S-shaped bodies was significantly lower (405±308) and the number of mature glomeruli (818±405) and layers of developing glomeruli (7.1±0.6) was significantly higher in the offspring of mothers on high-salt compared to the medium or low salt groups (1044±490, 460±304, and 5.9±0.9 respectively). As a net result the total number of glomeruli was significantly lower in the offspring of mothers on high-salt (9476±1264) compared to the medium or low salt groups (11175±1920). At 1 week of age in the offspring of mothers on high salt the glomeruli were bigger compared to lower salt intake. The expression of Pax-2 (54±23% vs. 100±28%) and FGF-2 (72±33% vs. 100±30%) was significantly lower in the offspring of mothers on high-salt consistent with their causative role. We conclude that high maternal salt intake during pregnancy accelerates maturation of glomeruli in the offspring, but reduces the final number of glomeruli.

Effect of sow history features on growth and feed intake in grow-finish pigs1

The sow provides a specific environment to her offspring during gestation and lactation. Certain features in the early life of the sow (sow history features) may affect her ability to deliver and feed a healthy litter. In genetic analyses of grow-finish traits, these effects are estimated as common litter or permanent sow effects. The objective of this research was to identify sow history features that affect the growth rate (GR) and feed intake (FI) of her offspring during the grow-finish stage. Data from 17,743 grow-finish pigs, coming from 604 sires and 681 crossbred sows, were recorded between May 2001 and February 2010 at the experimental farm of the Institute for Pig Genetics (Beilen, the Netherlands). The grow-finish stage was divided into 2 phases (phase 1: 26 to 75 kg; phase 2: 75 to 115 kg). The sow history features were birth litter size, birth year and season, birth farm, weaning age, age of transfer to the experimental farm, and age at first insemination. The sow features were added to the basic model one at a time to study their effect on the grow-finish traits of the pigs. Subsequently, significant sow features (P < 0.1) were fitted simultaneously in an animal model. With every extra piglet in the birth litter of the sow, the GR of her offspring decreased by 1 g/d and the FI decreased by 4 g/d. Every extra day to the first insemination increased the GR of grow-finish pigs by 0.1 g/d. The heritability estimates for GR and FI (only in phase 2 of the grow-finish stage) decreased after adding the sow features to the model. No differences were found in estimates of the common litter effects between the basic model and the model with all significant sow features. The estimates of the permanent sow effect changed for FI from 0.03 (basic model) to 0.00 (model with sow features), and for FI in phase 1, the permanent sow effect decreased from 0.03 (basic model) to 0.01 (model with sow features). In conclusion, selected sow features do affect the grow-finish traits of the pigs, but their estimates are small and explain only a small proportion of the differences in the GR and FI of grow-finish pigs. The sow features partially explained the permanent sow effect of FI-related traits and did not explain the common litter effect. Although the sow early life features can affect piglet traits, they do not predict which sows produce better performing offspring in the grow-finish stage.

Reproductive characteristics of a captive colony of big-eared climbing rats (Ototylomys phyllotis)

The authors analyzed the breeding characteristics of a colony of Ototylomys phyllotis (big-eared climbing rat) from Campeche, México, that was bred in captivity for 6 y. The big-eared climbing rat is a reservoir of Leishmania (Leishmania) mexicana, a causal agent of localized cutaneous leishmaniasis on the Yucatán Peninsula. The colony had been established to facilitate studies analyzing the effectiveness of O. phyllotis as an experimental model for L. (L.) mexicana. The authors describe the housing and husbandry of the colony, the procedures used for mating the animals and the behavior of the animals during mating. They report that the animals showed social behavior and could be bred successfully. Most breeding pairs successfully produced litters; some pairs produced more than one litter. The authors also report data for other parameters, such as the interval between pairing and birth or between births of consecutive litters, litter size, survival to weaning, the timing of sexual maturity and the effects of breeder age on breeding success.

THE PERFORMANCE OF ANGORA RABBIT DOES AND THEIR PROGENY DEPENDING ON THE SEMEN USED FOR ARTIFICIAL INSEMINATION

German Angora does were artificially inseminated with either Pannon White (N) or heterospermic (N+A) or Angora (A) rabbit semen to compare the reproduction and growth traits of 54 N x A, 53 (N+A) x A and 65 A x A matings. The kindling rate was 59.3, 58.5 and 47.7%, resp., the value of total born per litter averaged 7.09, 6.36 and 6.19, litter size at 21 days of age 5.73, 5.97 and 4.89, and litter weight at 21 days 1739, 1700 and 1446 g. In the (N+A) x A group the ratio of NA and AA offspring at 21 days of age was 70.1 % and 29.9%, which differed from the expected 1 :1 distribution (P<0.05). Rabbits were weaned at 42 days of age. For 91 NA from N x A, 74 NA and 30 AA from (N+A) x A, and 94 AA offspring from A x A mating combinations, the body weight averaged 317, 287, 288 and 303 g at 21 days and 1054, 993, 869 and 908 g at 42 days, and 2004, 1891 , 161 O and 1594 g at 70 days, and the daily weight gain between 3 and 6 weeks of age was 35.0, 33.6, 27.7 and 28.8 g and between 6 and 10 weeks of age 33.4, 32.1, 25.4 and 24.7 g, respectively. lt seemed that the Angora sperm disadvantageously influenced the fertility and litter size. The larger birth litter size, better gain and lower mortality of NA and their higher ratio in the heterospermic group indicated their better viability comparad to AA rabbits. The body weight of NA born in the heterospermic group differed more and more with advancing age from their AA littermates, which supports the hypothesis of the negativa pleiotropic effect of the Angora gene and/or the remaining part of the genoma on growth.

Estimation of genetic trends in French Large White pigs from 1977 to 1998 for growth and carcass traits using frozen semen12

Genetic trends for growth, feed efficiency, composition, and morphometry of carcasses were estimated in a French Large White (LW) pig population using frozen semen. Two groups of pigs were produced by inseminating LW sows with either stored, frozen semen from 17 LW boars born in 1977 or with semen from 23 LW boars born in 1998. In each group, 15 males and 90 females were randomly chosen and mated to produce approximately 1,000 pigs/group. These pigs were performance tested with individual ADFI and serial BW and backfat thickness measurements, slaughtered at 105 kg of BW, and measured for carcass traits. The data were analyzed using mixed linear animal models, including the fixed effect of the experimental group (offspring of 1977 or 1998 boars), the random effect of the additive genetic value of each animal, and, when significant, the fixed effects of sex, fattening batch, and slaughterhouse, the linear regression on BW, and the random effect of the common environment of birth litter. For each trait, the genetic trend was estimated as twice the difference between the 2 experimental groups. Results showed moderately favorable trends for on-test ADG (3.7 +/- 1.3 g/d per year) and feed conversion ratio (-0.014 +/- 0.005 kg/kg per year) in spite of a tendency toward an increase in ADFI (7.6 +/- 4.7 g/yr). A strong reduction in carcass fatness (-0.35 +/- 0.07 mm/yr for carcass average backfat thickness) and a large improvement in carcass leanness (0.31 +/- 0.10 mm(2)/yr and 0.41 +/- 0.08%/yr for loin eye area and carcass muscle content, respectively) were observed. Carcass shape measurements (back and leg length, back width, muscle thickness of hind limbs) were not affected by selection. Serial measurements of BW and backfat thickness showed that the major part of the genetic gains occurred during late growth and that the reduction in the backfat layer was more pronounced in the rear than in the front part of the carcass. The use of frozen semen appears to be a powerful practice to thoroughly investigate changes attributable to selection.

Female prairie vole mate-choice is affected by the males’ birth litter composition

Experimental testing and retrospective examination of breeding records were used to examine the influence of sex composition and/or size of males’ birth litters on female mate-choice. Sexually naïve female prairie voles ( Microtus ochrogaster) avoided males derived from all-male litters, but showed no preference for, or aversion to, males from single-male litters or from more typical mixed-sex litters. Examination of the pregnancy status of females after two weeks of pairing with a male allowed us to estimate the probabilites of a pups’ intrauterine position relative to siblings for various litter sizes. The typical prairie vole pup derived from a mixed-sex litter comprised of 4.4 pups, and had a 13% chance of being isolated from siblings in utero and a 22% chance of being between siblings in utero. Pups from single-sex litters tended to be larger at weaning than did pups from mixed-sex litters; however, male size did not influence female choice behavior. These results suggest that some aspect of the perinatal experience of prairie vole pups from single sex litters can influence social interactions later in life.